We are currently evaluating Aspose.Words. We uploaded a docx with content controls in the online demo, but it seems to remove them or convert them to plain text. Does Aspose.Words for the browser support adding/editing content controls?
Could you please share the online demo where you are uploading your document? Please ZIP and share your input Word document along with steps that you are using to reproduce the same issue at our end. We will investigate the issue and provide you more information on it.